Hello all,

I have tried finding out this on PT.net and thought I would try my luck here. I have searched on tones of sites and forums have not luck. Anyway I am dealing with a huge issue that has plagued me and my tunner through two engines.

I am running a 04 silverado ecsb lq4 prc 2.5 5.3 heads, toruqer v2 cam, tbss intake, lts, no cats, gibson exhaust, mild built Tranny, tuned my Bryan Herter from PCM for less.

I previously had a 5.3, 243 heads, 224/224 cam, tbss intake, lts, no cats, gibson exhaust. 343 rwhp tuned my Bryan Herter from PCM for less. (blown to smitherines)

Ok what has been happening is when in second gear and above when I am at wot and I hit redline and shift. I stay stuck in open loop or PE. My ltfts will still move but my stfts are zero and my o2's are at 0.9. If I wind out in first this does not happen. Only 2nd and third. The only way for this to reset to closed loop is to turn the truck off for a min. I am running a blue tooth with Torque app. I have also tried this on another app called OBD DroidScan and I get the same result. I have not verified this with HPT or another direct connection scan software yet. I have no vacuum leaks and other then this the truck runs great. This issue has happened with both motors so it is in either the tune, the loom or a sensor.

Things i have tried so far.
Replaced MAF
Replaced O2's
swapped PCMS
Rebuilt tune from another 6.0

I have tried shutting both apps off and unplugging and restating the apps to see if it was an app issue. Not luck

I am at a loss and so is Bryan. The last street tune we (he) was able to get the ltfts to stay on before the ltfts stayed at 0 also. Because the ltfts move after i let off leads me to believe it is not pe but getting stuck in open loop for some reason.

I would appreciate any help in trouble shooting or is anyone has dealt with this before.

Thank you for your help

 

Post your tune and a log.

 

What are your PE "RPM Hyst" and "MAP Hyst" set at?
When I initially setup my tune I misinterpreted the MAP Hysteresis setting and set it at my target PE disable MAP. The Hyst is actually supposed to be set as the amount below your enable you want it to disable.

So for instance when I set enable to 85 and Hyst to 79.... It wont actually disable until the map drops all the way to 6kpa.....which doesn't happen on a running engine.

The correct setting in my case is 85 enable and 6 Hyst. This will disable PE at 79kPa.

The same mistake could be made with the RPM setting.

 

I wish I could post my my tune or log. I currently do not have a copy of HP tuner or the like. The only thing I can do is monitor through torque app on my phone.

I will pass the info on to Bryan. Although My issue is not getting into open loop or PE its that It will not come back to closed loop but only if I hit my shift point at wot. If I am wot in PE below that say at 5000 I will come right back out.

I am going to try another pcm that is year and model specific and start over.

I wonder if this is an xlink issue at all. It seems that some limit is being hit that we are missing and sending the tune into a non learn.

Bryan has years of experience with nothing by GM vehicles and this is a first for him.

anyway thanks for the input. I will let you know how this ends up

 

Check out cat overtemp protection (COT) and
whether your commanded AFR just happens to
match the values in those tables.

COT likes to roll on after a hard pull and once it
has, it hangs around waiting for any excuse to
reapply.

I make my COT tables use the same commanded
AFR as what PE and open loop EQ are, so if it
comes on, it doesn't bother anything.

 

How about just disabling it?